The present invention relates to a method of solidifying low-boiling-point hydrocarbons (e.g., hydrocarbons that are liquid with a high vapor pressure at ordinary temperature, as well as hydrocarbons that are gaseous at ordinary temperature), a method of regenerating this solidified product into low-boiling-point hydrocarbons in the original state, and a method of handling low-boiling-point hydrocarbons by utilizing these methods.
As the scale of the petrochemical industry is enlarging year by year, organic compounds are produced and consumed in a large amount, and further, natural gas is used in a large amount. In this connection, pollution and accidents threatening the existence of mankind and living creatures, such as environmental pollution, water pollution, pollution of the ocean by tanker accidents; fires, and explosion accidents, occur frequently and worldwide, and the handling of organic compounds, including petrochemical materials, is an important issue. One cause for such pollution and accidents is mistakes made by people or inadequate safety measures, such as incomplete combustion, leakage, and release. Another and essential cause is, as a matter of course, that many of the organic compounds that have caused pollution and accidents are highly volatile liquids or gases. In particular, a basic requirement in the petroleum chemistry and the natural gas chemical industry is that gaseous organic substances can be handled safely at ordinary temperature.
In addition, the method of handling organic compounds used as industrial raw materials during storage and transportation, as well as costs thereof, is greatly influenced by the gaseous state of most such organic compounds. This is a fundamental problem in modern petrochemistry, including utilization of natural gas, and this is not an issue that can be solved by switching to carbochemistry or to utilization of solid fuels, such as charcoal.
As to this problem, it is proposed that gaseous organic compounds should be handled in a safer state during storage, transportation, etc. Attempts at this include handling an organic gas, such as methane, as a stable hydrate, i.e. methane hydrate (generally gas hydrate), by inclusion thereof into a cage structure formed by hydrogen bonds of water molecules, but it cannot be said that this attempt has been completed as practically usable techniques. Further, methane hydrate (gas hydrate) essentially requires several times or more water molecules than organic gases, and thus a very large amount of unnecessary water must be handled simultaneously.
In the case of hydrogen, for example, a hydrogen-occlusion alloy, which can reversibly occlude and release a hydrogen gas repeatedly, has been proposed, but for organic compounds, no such substance capable of reversible occlusion and release has been found.
Accordingly, it is desired that low-boiling-point liquid hydrocarbons and gaseous hydrocarbons can be handled as safe solids during storage, transportation, etc., while the original hydrocarbons can be taken out from the solid when used. It is considered that the requirements for such solidified materials of hydrocarbons are, for example, that they must be (1) repeatedly usable, (2) chemically relatively stable, and (3) safe and harmless, because their use in a large amount is estimated, and they are less dangerous even if they are discharged to the outside of the storage system.
Proposed methods of solidifying organic compounds that are liquid at ordinary temperature are described in JP-A-55-75493 (xe2x80x9cJP-Axe2x80x9d means unexamined published Japanese patent application) and JP-A-59-142274, but these methods involve utilizing hydrophilic groups in the compounds, thereby incorporating water and solidifying the compounds. Further, there is no description therein of a method of solidifying hydrocarbons that are gaseous or highly volatile liquid at ordinary temperature, and the solids described in these literatures cannot be reused when necessary by decomposition, to take out only hydrocarbons therefrom.
Accordingly, an object of the present invention is to provide a method of realizing reversible solidification of low-boiling-point hydrocarbons (including hydrocarbons that are gaseous at ordinary temperature) by utilizing materials satisfying the conditions as described above; that is, an object of the present invention is to provide a method of solidifying low-boiling-point hydrocarbons, a method of taking out low-boiling-point hydrocarbons in the original state from the solidified product, and a method of handling low-boiling-point hydrocarbons by using these methods.
Other and further objects, features, and advantages of the invention will appear more fully from the following description, taken in connection with the accompanying drawings.